﻿namespace org.apache.lucene.analysis.hi
{

	/*
	 * Licensed to the Apache Software Foundation (ASF) under one or more
	 * contributor license agreements.  See the NOTICE file distributed with
	 * this work for additional information regarding copyright ownership.
	 * The ASF licenses this file to You under the Apache License, Version 2.0
	 * (the "License"); you may not use this file except in compliance with
	 * the License.  You may obtain a copy of the License at
	 *
	 *     http://www.apache.org/licenses/LICENSE-2.0
	 *
	 * Unless required by applicable law or agreed to in writing, software
	 * distributed under the License is distributed on an "AS IS" BASIS,
	 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	 * See the License for the specific language governing permissions and
	 * limitations under the License.
	 */

	using org.apache.lucene.analysis.util;
//JAVA TO C# CONVERTER TODO TASK: This Java 'import static' statement cannot be converted to C#:
//	import static org.apache.lucene.analysis.util.StemmerUtil.*;

	/// <summary>
	/// Normalizer for Hindi.
	/// <para>
	/// Normalizes text to remove some differences in spelling variations.
	/// </para>
	/// <para>
	/// Implements the Hindi-language specific algorithm specified in:
	/// <i>Word normalization in Indian languages</i>
	/// Prasad Pingali and Vasudeva Varma.
	/// http://web2py.iiit.ac.in/publications/default/download/inproceedings.pdf.3fe5b38c-02ee-41ce-9a8f-3e745670be32.pdf
	/// </para>
	/// <para>
	/// with the following additions from <i>Hindi CLIR in Thirty Days</i>
	/// Leah S. Larkey, Margaret E. Connell, and Nasreen AbdulJaleel.
	/// http://maroo.cs.umass.edu/pub/web/getpdf.php?id=454:
	/// <ul>
	///  <li>Internal Zero-width joiner and Zero-width non-joiners are removed
	///  <li>In addition to chandrabindu, NA+halant is normalized to anusvara
	/// </ul>
	/// 
	/// </para>
	/// </summary>
	public class HindiNormalizer
	{
	  /// <summary>
	  /// Normalize an input buffer of Hindi text
	  /// </summary>
	  /// <param name="s"> input buffer </param>
	  /// <param name="len"> length of input buffer </param>
	  /// <returns> length of input buffer after normalization </returns>
	  public virtual int normalize(char[] s, int len)
	  {

		for (int i = 0; i < len; i++)
		{
		  switch (s[i])
		  {
			// dead n -> bindu
		  case '\u0928':
			if (i + 1 < len && s[i + 1] == '\u094D')
			{
			  s[i] = '\u0902';
			  len = StemmerUtil.delete(s, i + 1, len);
			}
			break;
		  // candrabindu -> bindu
		  case '\u0901':
			s[i] = '\u0902';
			break;
		  // nukta deletions
		  case '\u093C':
			len = StemmerUtil.delete(s, i, len);
			i--;
			break;
		  case '\u0929':
			s[i] = '\u0928';
			break;
		  case '\u0931':
			s[i] = '\u0930';
			break;
		  case '\u0934':
			s[i] = '\u0933';
			break;
		  case '\u0958':
			s[i] = '\u0915';
			break;
		  case '\u0959':
			s[i] = '\u0916';
			break;
		  case '\u095A':
			s[i] = '\u0917';
			break;
		  case '\u095B':
			s[i] = '\u091C';
			break;
		  case '\u095C':
			s[i] = '\u0921';
			break;
		  case '\u095D':
			s[i] = '\u0922';
			break;
		  case '\u095E':
			s[i] = '\u092B';
			break;
		  case '\u095F':
			s[i] = '\u092F';
			break;
			// zwj/zwnj -> delete
		  case '\u200D':
		  case '\u200C':
			len = StemmerUtil.delete(s, i, len);
			i--;
			break;
			// virama -> delete
		  case '\u094D':
			len = StemmerUtil.delete(s, i, len);
			i--;
			break;
			// chandra/short -> replace
		  case '\u0945':
		  case '\u0946':
			s[i] = '\u0947';
			break;
		  case '\u0949':
		  case '\u094A':
			s[i] = '\u094B';
			break;
		  case '\u090D':
		  case '\u090E':
			s[i] = '\u090F';
			break;
		  case '\u0911':
		  case '\u0912':
			s[i] = '\u0913';
			break;
		  case '\u0972':
			s[i] = '\u0905';
			break;
			// long -> short ind. vowels
		  case '\u0906':
			s[i] = '\u0905';
			break;
		  case '\u0908':
			s[i] = '\u0907';
			break;
		  case '\u090A':
			s[i] = '\u0909';
			break;
		  case '\u0960':
			s[i] = '\u090B';
			break;
		  case '\u0961':
			s[i] = '\u090C';
			break;
		  case '\u0910':
			s[i] = '\u090F';
			break;
		  case '\u0914':
			s[i] = '\u0913';
			break;
			// long -> short dep. vowels
		  case '\u0940':
			s[i] = '\u093F';
			break;
		  case '\u0942':
			s[i] = '\u0941';
			break;
		  case '\u0944':
			s[i] = '\u0943';
			break;
		  case '\u0963':
			s[i] = '\u0962';
			break;
		  case '\u0948':
			s[i] = '\u0947';
			break;
		  case '\u094C':
			s[i] = '\u094B';
			break;
		  default:
			break;
		  }
		}

		return len;
	  }
	}

}